Fluid compressor



` Oct. 15, 1935. P..| czru'rTErqvrarg-N 2,017,684

. FLUID coMPREssoR Filed OCT... 3l, 1935 Figa.

82 l INVENTR q PHILIPLCRITTENDEN Patented 15, 1935 .UNITED STATES PATENT OFFICE lFLUID comaasson Philip n Crittenden, Edgeweea, re., saigner te The Westinghouse Air- Brake Company, Wilmerding, Pa., a corporation of Pennsylvania' Application October 31, 1933, Serial No., 695,99'5

l v12 claim.

This invention relates to fluid compressors and v particularly to the lubricating and unloading devices for fluid compressors.

` An object of the invention is to provide an,

improved lubricating system for the 4compressor and a fluid pressure controlled unloader device that is responsive to variations in thepressure of the fluid lubricant of'said system for effecting unloading of the compressor when the lubricant l0 pressure is low, as when the compressor is at rest or as when the lubricating system fails, and to effect loading of the compressor only when the lubricant pressure is increased to a predetermined value, as when the compressor has attained a vpredetermined speedof operation. suitable for assuming'the load. 1

A further object of lthe invention is to provide vaeeuid lubricant pressure controlled loading device having the above notedcharacteristics and having an unloading' valve remote from the come pression cylinder and wherein means are provided for minimizing the clearance of the unload- A further object of the invention is to provide a combined lubricating and unloading device for a. compressor that is readily accessible through removal of a single portion of the crank case.

A further object of the invention is to provide improved crank case construction for a compressor, whereby fluid lubricant is conveyed by gravity from the illling opening to thecrank shaft bearing through open channels that may readily be formed with a simple core construction-when the crank case is being cast. yT'hese and other objects that will be made apparent throughout the further description of the invention. arefattained by means ofthe compresser construction hereinafter described and o illustrated in the accompanying drawing; where- Fig. 1 is a vertical sectional view through a single stage compressor 'embodying/ features of the invention;

Fig. 2 is a section through a fragment of the crank case, taken on the line 2-2 of Fig. 1;

Fig. 3 is a section through a fragment of the `crank case, taken on the line 43---3 of Fig. 1, and

Fig. 4 is a section through a fragment of the crank case, taken` on the line 4-4 of Fig. 1.

` Referring to the drawing, the compressor comprises a sectional casing consisting of a crank case l, a cylinder section 6 and a. cylinder head section 1, the casing section 5 being provided v with a crank chamber I having a relatively large the discharge valve device 26 is caused to open (Cl. 23o-21) end opening Sthat is closed by a closure casing il which is secured to the casing 5 by means of bolts i2, one of whichis shown. The casing section l is provided with a cylindrical bearing chamber `i3 in which anti-friction bearings il 5V are secured for supporting the rotatable crank shaft i5 whichextends exteriorly of the casing through an opening i8 in a' closure member i1 that is secured to the casing by meansof bolts, not shown. A packing ring. i8 in the closure 10 member I1 serves to seal the space between the closure member and the crank shaft and prevent e lubricant from flowing exteriorly of the casing.v Thecompressor may be drivenby any form of motor device, such as an electric motor or an 1,5

internal combustion engine that is connected 'to the crank shaft i5.

The crank shaft Il is provided with a counterbalanced crank arm I9 having a crank pin 2i to which the connecting rod 22 of a compression 20 piston 23 is connected in the usual manner, so that as, the crank shaft is rotated the piston 23 is reciprocated within the bore 24 of the cylinder casing 8 in the well known manner.

' As in the usual single stage compressor,l the 25 initial upward movement nf the piston in the compression stroke, and when the pressure within the chamber 21 becomes higher than the pressure within the receiver which is connected to lthe'disclfiarge valve device 26 through a pipe 28, 40

- and to permit the compressed fluid within the chamber 21 to iiowzintothe receiver through -the pipe, 20. The valves 25A and 26 may be of any preferred construction.'

The connecting rodbearing ,29 is lubricated. 45.

by fluid lubricant supplied thereto throughla passage .3i in a portion of the crank pin 2i which is suppliedr with fluid lubricant from a recip- -l rocating pump. The fluid lubricant circulating pump comprises a hollow piston 32 that is pivotally mounted upon a crank pin 33 which is integral with crank pin 2i and which is eccentric tok the center of rotation of the crank shaft i5, $0 that' as the crank shaft I5 is rotated the piston 55 l -v lower end with an inlet port check valve 45. IA pin ypreventing foreign particles from owing to the inlet opening 31. 'I'he inlet opening- 31 registers with an opening 39 in a bore 4| within the -cylinder member which is open to the chamber 34, and the opening-39 is provided .with a ballv check valve 42 which serves to permit vfluid lubricant to now from thecrank case into the bore 4i, but which prevents a reflux of the iiuid from'the bore 4|. Y f

The piston 32 is provided with a longitudinal bore 43 which communicates with the passage 3| in the crank pin 33 and which is provided at its 44 having a ball 46 extending across the piston within the bore 43 serves to limit :the upward movement of the ball check valve 85.

The cylinder member 35 is also provided with a 'piston chamber 48 containing a piston 49. Fluid lubricant is forced into the chamber 48 from the piston chamber 84 through bore-4|, passage 5I, past the ball check valve 52 in a valve chamber 53 andpassage 54.

passage 3|, from whence Itis apparent from the foregoing, that when the cranlr shaft 5 isA rotate'd, the piston 32 is reciprocatedy within the piston chamber 34 of the cylindermember 35 and that upon theupward stroke of the piston 32, uid lubricant is drawn from the crank case chamber 8 through screen 38, passage 31, past theballcheck valve 4,2, the ball check valve 45l in the piston being seated upon the upward stroke of the piston 32. Upon the downward'stroke of the piston k32,1the uid lubricant drawn into the piston chamber 34 beneath the 'piston is forced through the passage 44,'past the balll check valve 45 and into the it flows to the connecting rod bearing 29. Since there is no outlet ior the iluid lubricant except through the clearance space of the bearing 29, the piston 32 compresses the fluid within the chamber 3 4 and forces it under pressure into the piston chamber 48 through the bore 4I', passage 5|, past the ball check valve 52 and passage 54, and the 'fluid under pressure acting on the left face of the piston 49 tends to move the piston 43 to the right position, as will hereinafter be explained.

The compressor is provided with an unloader device which comprises a ball check valve 55 conclosure casing A es tained within a valve chamber 58 in the closure casing I, the valve being normally held unseatd, when the compressor is at rest. by a iiuted stem 51 which iextends through a bore 58 and which is operated by a lever 58 that iis mounted for oscillation upona shaft 8| secured to the closure casing II. A spring 82 within a recess 83 in the II engages the lower arm of the lever 59 and serves to yieldingly retain the lever -59 in the position shown in the drawing, wherein the lever and fluted stem 51 hold the ball check *valve 55 in open position. A spring 84 within the valve chamber 55 tends vto move the ball check valve 55 to closed position when the lever 5921s rotated in a counter-clockwise direction by the piston 49 which is provided with a stem 85 that engages the lower end of the lever 58.

The valve chamber 58 communicates with the compression chamber 21 i: above the piston 23 through a passage and pipe 58, check valve chamber 81 and passage 88 which is normally closed by a. ban check valve n that is yielainsiy retained pipe 88, valvecha'mber against its seat by means of a spring 1I. The

`operation of the unloader device will hereinafter appeal.

The closure casing is provided with a lling opening 12 that is normally closed by a hinged o cap 13 which carries a check valve disc 14 upon a pin 15, the disc being adapted to seat upon an annularv seat rib 18 and prevent air from flowing through the iilling openinginto the crank case. The valve disc 14 is adapted to be unseated le when the pressure within the crank case chamber 8 exceeds atmospheric pressure and to thereby relieve the pressurel within the 'crank case chamber. Upward movement of the valve disc I4 is limited by a seat `rib11 carried by the cap 15 member 13.

In order to insure lthat fluid lubricant is supplied to the bearing chamber I3 when duid lubricant is poured through the iilling opening into the crank case, the casing 5 is provided with an 20 arcuate iiange 18 which forms an arcuae chan nel or groove 19 above the opening 9 in the casing 5. into which lubricant ows from the filling opening 12 through opening 8|. The lubricant flowing into the groove 19 'is conducted along a 25 horizontal channel 82 formed in the sidewall of the casing section 5 to the bearing chamber i3 through an opening 83. Consequently, when fluid lubricant is poured into the filling openingi it is conducted through. passage 8i, groove 19, 30 groove 92, and passage 83 to the bearing chamber I3 from whence it overows past the bearings I4 ino the crank chamber 8.

A threaded gage opening 84 is provided in the closure section |I and which is so disposed that 85 when suiiicient fluid lubricant has been supplied to the crank case, lubricant will iiow from the gage opening. The gage opening is adapted to be closed by a threaded stopper-85 having a gage member 88 integral therewith and which extends c into the crank chamber 8. The level of the fluid lubricant-within the crank chamber may be determined by unscrewing the stopper 85 and observing the location ofl the oil on the gage member 38. 45

In operation, assuming the parts of the compressor to be in the position shown in Fig. i,

which they occupy when the compressor is at rest, and the ball check valve 55 of the unloader to be in the open position shown, initial operationv of 5o Ihe compressor will simply cause the air drawn into the compression chamber 21 upon the downward or Vsuction stroke to be forced, upon the upward or compression stroke of the piston, pastl the ball check valve 89 to the atmosphere through 55 58,-past the open ball valve 55, bore 58, crank case chamber 8, pas- .sage 8 filling opening 12, past the breather check valve disc 14, `and through the passage 81 in the cap 13. The compressor will, therefore, remain 80 unloaded so long' as the ball check valve 55 is held open.

As the compressor continues to rotate with increased speed, reciprocation of the pump piston 32 will gradually cause the pressure of the iluid g5 lubricant within the piston chamber 34 to `increase, thereby increasing the pressure of the fluid lubricant acting on the left face of the piston 49. The movement of the piston 49 to the right is opposed by the tension of the spring 82, which ten- 70 sion is so'selected that it prevents movement of the piston 49 until the compressor has attained a speed suitable for assuming the load.

When the compressor hasattained the desired speed of operation, Athe pressure 'of the iiuid iubriu n cant'acting on the piston I9 then forces it to the right against the tension of the spring 82, thereby causing counter-clockwise rotation of the lever 59 until it provides clearance between the lever and the iluted stem 51, at which ltime the check valve 55 is moved to close the bore 58 by .the spring 6I. With the check valve 55 closed, iiuid under pressure can no longer ilow to the atmosphere past the check valve 68 in the manner previously described, so that the iluid must be compressed and forced into the receiver through the pipe 28 in the usual manner.

- In. order to prevent the pressure within the lubricating system from becoming excessive, a port 9i is provided in the cylinder 41 lwhich is uncovered by the piston 49 when the latter has moved to the right suillciently to permit closure of the ball check valve 55 and uid forced from the piston chamber 34 to the piston chamber 48 past the check valve 52 may then ilow to the crank case chamber 8 through the port Il.

With the ball check valve 55' held closed by the spring 64 and the pressure within the chamber 56,- the compressor is loaded and will remain loaded until such time as the. compressor speed is reduced suiilciently to cause a reduction in the pressure of the iluid lubricant in the lubricating system. so that the spring 62 may torce the piston I9 to the left and turn the lever 59 so as to unseat the check valve 55.- 'From the foregoing it is apparent that the compressor is unloaded when the' compressor is brought .to rest or when. for any reason. the pressure of the lubricant in the lubricating system falls below a predeterminedipres- With the ball check valve 55 in unseated position. the air compressed by the'compressor piston 23 within the chamber 21 ows to the atmosphere past the ball check valve 89, in the manner above described. The ball check valve 89 is located immediatelv adjacent the compression chamber 21. so that the clearance o! the unloader'is limited to that oi the short passage $8 when tbe ball check valve is held closed by the spring 'H and the pressure oi.' the fluid in pipe $8 and when the ball check valve 5S is closed, as when the compressor is loaded. A

While but one embodiment o! the invention is herein disclosed, it is obvious that additions. omssions and other changes may be made in the construction without departing from the spirit of the invention.

Having now described my invention. what I claim as new and desire to secure by Letters Pat-v ent,is:

l. The combination with a compressor, of an unloader comprising a check valve controll'ng communication from a chamber in which fluid is compressed to the atmosphere. means normally yieldingly holding said check valve in closed postion, yielding means for holding said check valve open. a pump actuated by the compressor for circulating iiuid lubricant under pressure in said system and a movable abutment actuated by fluid lubricant in said system for rendering said yielding means ineiiective to hold said check valve open.

2. The combination w'th a compressor, oi' an unloader comprising a valve controlling communication from a chamber. in which iiuid is compressed. to the atmosphere, means normally yieidingly holding said valve in closed position, yielding means for holding said valve open, a pump actuated Ly the compressor for circulating iluid lubricant under pressure, a movable abutment actuated by the pressure oi fluid lubricant circulated by the pump fcr'rendering said yielding means ineiective to hold said valve open, a'in means controlled by said abutment for regulating the pressure of the lubricant circulated by said 5 pump.

3. A iluid compressor comprising a casing having a compression chamber and a crank case chamber', an unloading communication leading from the compresson chamber through said crank case chamber to the atmosphere, a valve for controlling said communication, yielding,r means for holding said valve in closed position, a second yielding means for holding said valve in open position x'n opposition to s aid first yielding means, and pressure responsive means for rendering said second yielding means ineffective to hold said valve in open position.

4. A iiuid compressor comprising a casing having a compresson chamber and a crank case chamber, an unloading communication leadnr. from the compressionchamber through said crank case chamber to the atmosphere. a check valve adapted to permit ilow of duid under pressure through said communication from said crank case chamberv to theatmosphere and to prevent vilow of iluid therepast in the opposite direction, a valve for controllng said communication, yielding means for holding said valve in closed position, a second yielding means for holding said'valve in open position in opposit'on to Asaid ilrst yielding means, and pressure responsive means tor renderingisaid second yielding means ineffective to hold said valve in open position.

5. A iluid compressor comprising a casing having a compression chamber and a crank case chamber. a check valve adapted to permit the tlow of iluid under pressure from the said crank case chamber to the atmosphere but preventing reverse flow therepast. a communication for they tlow of fluid underl pressure from the said compression chamber to said crank case chamber, a valve for controlling the ilow of fluid under pressure through said communication from the said compression chamber to the said crank case chamber, yielding means for holding said valve in closed posit'on, means including a second yielding means for holding said valve in open position in opposition to said first yielding means, and pressure responsive means for rendering said means ineffective to hold said valve in open position when the pressure acting on said pressure responsive means exceeds a predetermined valve.

6. A fluid compressor comprising a casing having a compression chamber and a crank case' chamber, a check valve adapted to permit the ilow oi i'iuid under pressure from the said crank case chamber to the atmosphere but preventing reverse flow therepast, a communication for the tlow of iluid under pressure from the said come0 pression chamber to said crank case chamber, a valve -for controlling the ilow of iiuid under pressure through said communication from the said compression chamber to the said crank case chamber, yielding means for holding said valve e5 in closed position, means including a second yielding means for holding said valve in open position in opposition to said iirst yielding means, and pressure responsive means controlled by the speed oi the compressor for rendering said means ineirective to hold said valve in open position when the speed of the compressor exceeds a predetermined value.

'1. A :luid compressor comprising a casing having a compression chamber and a crank case u chamber, a check valve adapted to permit the flow of iluid under pressure from the said crank case chamber to the atmosphere but preventing reverse iiow therepast, a communication for the flow of fluid under pressure from the said compression chamber to said crank case chamber, a valve for controlling the flow of iiuid under pressure through said communication from the said compression chamber to the said crank case chamber, yielding means for holding said valve in closed position, an operating lever within said crank case chamber adapted to move the said valve to open position, a second yielding means adapted to cause said lever to move said valve to and hold it in open position in opposition to said first yielding means, and pressure responsive means within the crank case chamber adapted 'to oppose -the movement of said operating lever by said second yielding means and render it ineffective to hold said valve in open position.

8. Aiiuid compressor comprising a casing having a compression chamber and a crank case chamber communicating with the atmosphere, a conduit for establishing a communication from said compression chamber to said crank case chamber whereby said compressor may be unloaded, a check valve in said communication adjacent said compression chamber adapted to permit flow of fluid under pressure from said compression chamber into said conduit and to prevent reverse flow therepast, a valve in said communication for controlling the flow of iiuid under pressure therethrough, yieldingmeans for holding said valve inv closed position, a second yielding means for holding said valve in open position in opposition to said ilrst yielding means, and pressure responsive means for rendering said second yielding means ineffective to hold said valve in open position when the pressure Aacting on said pressure responsive means exceeds a predetermined value. l

9. A iiuid compressor comprising a casing hav ing a compression chamber and a crank case chamber, said crank case chamber being open at one face thereof, a casing section secured to said casing and closing the open face of said crank case chamber, an unloading valve mounted in said casingsection and controlling communication from said compression chamber to said crank case chamber, and means for operating said valve.

l0. A iiuid compressor comprising a casing having a compression chamber and a cranl: ce e chamber, said crank case-chamber being open at one face thereof, a casing lsection secured to said casing and closing the open face oi said crank case chamber, an unloading valve mounted in said casing section and controlling communication from said compression chamber to said crank case chamber, and an operating lever pivotally mounted withinsaid casing section for operating said valve.

1l. A iiuid compresor comprising a casing having a compression chamber and a crank case chamber, said crank case chamber being open at one face thereof, a casing section secured to said casing and closing the open face of said crank case chamber, an unloading valve mounted in said casing section and controlling communication from said compression chamber to said crank case chamber, means for operating said valve,

and a check valve mounted in said casing section adapted to permit the flow of iluid under pressure from said crank case chamber to the atmosphere and preventing reverse iiow of iluid theref past.

l2. A fluid compressor comprising a casing having a compression chamber and a crank case chamber, said crank case chamber being open at one face thereof, a casing section secured to said casing and closing the open face of said crank case chamber, said casing section having an opening therein through which fluid lubricant may be poured into the said crank case chamber, an unloading valve mounted in said casing section and controlling communication from said compression chamber to said crank case chamber, means for operating said valve, and a check valve, removably disposed in the opening in said casing section through which fluid lubricant may be poured into the crank case chamber, said check valve being adapted to permit the iiow o! fluid under pressure 4from said crank case chamber 'to the atmosphere and preventing reverse now of iiuid therepast.

- FHILIP L. CRII'I'ENDEN.

4 cnitr'rtcatre or coRRcnoN.

mm Nq. 2,011,534.

l mm1 1..'cnlmnns1v.

ltv is herehy certified that eNror appears'in the printed specification of the above numbered patent requiring correction as follows: Page 3, first column,

line 56. .beginning with the numeral nntltrord "l. The" strike outall to and including the word and period "opem" in line 67, comprising claim l; and for, the claim numbers "2, 3,-- 4. 5, 6, 7, 8, 9, l0, 1l and l2" read l, '2, 3, 4, 5, 6, 7, 8, 9, 10 and ll, respectively; page 3, second column, line 53, claim 5, for "valve" read value; and that the said Letters Patent should be read with these corrections therein that the seme may conform to the record of `the case in the Patent Office.

Signed and sealed this 14th day of January, A. D. 1936.

Leslie Frazer I (Seal) Acting Commissioner of Pntents.

" October l5. 1935. 

